The iPhone 5s connects like any other iPhone, or any phone for that matter. Turn on Bluetooth on your phone, follow the pairing instructions in the manual. I've had 3 different versions of iPhone connected 5s, 5 and 4s. Set was identical and painless on all of them.
By Sledman on December 16, 2013

Although I don't have first hand experience with the device, I can vouch that it has good (8-10) audio quality. I gave this as a gift to a friend and have spoken to him many times while he was using the Bluetooth set. The call quality was good. No need to yell into the mic. No problems hearing the conversation.
By Zak on September 10, 2013

Your phone will need to be turned on for bluetooth. This unit has capabilities to remember up to 10 devices, so as long as you have connected to this unit before all you have to do is turn on your car & push the button on the unit
By Ashley A on December 4, 2013